The invention relates to a hydraulically damped bearing with a first anchoring member and a second anchoring member that are arranged in a movable fashion to one another, with a spring element operating between the first and second anchoring members, with an operating chamber filled with a damping fluid and a compensation chamber separate from the operating chamber and connected to it via a channel that is defined by the channel walls and that allows the fluid to pass through. The volume of the operating chamber changes due to the relative movement of the first and second anchoring members, such that the damping fluid is moved in the channel between the compensation chamber and the operating chamber. The operating chamber and the compensation chamber are separated by a separating wall that is impacted by the damping fluid. This separating wall is held in position at the second anchoring member by a support object, where the support object includes at least a first and a second support object element which are adjacent in an axial bearing direction. The support object elements are braced against each other and form a first radial inner section of the channel wall.
A hydraulically damped bearing of this type is known from the German Patent No. DE 39 37 232 A1.
With the known hydraulically damped bearing, an elastic separating wall is provided between the operating chamber and the compensation chamber to isolate the higher-frequency vibrations stimulated by the motor. The open surface of the separating wall, that is, the surface of the separating wall facing the operating chamber, which is impacted by the damping fluid, is significantly smaller than the feed cross-section of the spring element. A relative movement of the first and the second anchoring members would change the volume of the operating chamber by moving the end of the operating chamber formed by the spring element and the first anchoring member towards the separating wall or away from the separating wall. Specified as the feed cross-section of the spring element is the area of an auxiliary piston that would displace the same volume upon moving the piston as the spring element and the first anchoring member.
With the bearing known from the aforementioned German Patent No. DE 39 37 232 A1, the open surface of the separating wall is significantly smaller than the feed cross-section. The structural space for the elastic separating wall is limited in that the damping channel is located in the support object stretching in a radial direction around the separating wall. The disadvantage of the bearing known from this German patent is that the progression of the dynamic spring rate is not yet optimal in the high frequency range between 150 and 600 Hz.
The German Patent No. DE 42 05 229 discloses a hydraulically damping rubber bearing having a first and a second anchoring member that are arranged in a movable fashion to one another, having a spring element operating between the first and second anchoring members, and having an operating chamber filled with a damping fluid and a compensation chamber separate from the operating chamber and connected to it via a channel that is defined by the channel walls and that allows the fluid to pass through. The volume of the operating chamber changes due to the relative movement of the first and second anchoring members, such that damping fluid is moved in the channel between the compensation chamber and the operating chamber. The operating chamber and the compensation chamber are separated by a separating wall that is formed by a support object and impacted by the damping fluid. The channel connecting the operating chamber and the compensation chamber is formed in an outer section of the one-piece support object and is defined, on the one hand, by the support object and, on the other hand, by a chamber housing that is located radially on the outside.
It is the objective of the invention to provide a hydraulically damped bearing that exhibits a particularly well suited progression of the dynamic spring rate, in particular in the high frequency range between 150 and 600 Hz.
This objective is achieved with a hydraulically damped bearing of the type described above, wherein a housing section that is formed at the second anchoring member forms a second radial outer section of the channel wall.
The present invention for the first time demonstrates how an enlargement of the open surface of the elastic separating wall can be achieved for a two-part design of the support object as well. With the housing section that is formed at the second anchoring member forming a radial outer section of the channel wall, the channel can be positioned further out in a radial direction. In this manner, it is possible to enlarge the open surface of the separating wall without shortening the channel length. A great channel length is of primary importance for effective vibration isolation of low-frequency vibrations.
According to one advantageous embodiment, it is provided that the support object is held in place in an axial bearing direction by a seating formed at the second anchoring member and in the radial direction of the housing section that at least partially surrounds the support object.
An additional improvement is achieved in that the housing section in the contact area of the support object, at least in a section, is tapered such that the support object is pressed against the seating. In this manner, the support object is held against the second anchoring member in a simple fashion.
According to a particularly advantageous embodiment of the invention, it is provided that the first support object portion that is in contact with the housing section is braced against the second support object portion that faces the seating through the tapered housing section. This design results in a particularly large open surface of the separating wall, because the channel that is limited by the first and the second support object element can be placed in a radial direction far to the outside, which increases the space for the elastic separating wall in the structural space.
According to a further development of this invention, an elastically sealing coating is included in the contact area of the first support object portion at the housing section. This not only permits bracing the two support object elements against one another under an elastic force, but at the same time dependably sealing the channel against the operating chamber as well.
Manufacturing costs are lowered in that the spring element is made of rubber and the elastically sealing coating is designed in one piece together with the spring element.
A high stability of the bearing is achieved in that the second support object element is held in direct contact to the seating by a connecting section of the second anchoring member.
Advantageously, the separating wall is braced between the two support object portions.
To avoid excessive movement of the separating wall, it is provided that an aperture plate that supports the separating wall is placed at least on one side of the elastically designed separating wall.
An additional increase of the open surface of the separating wall can be achieved in that the separating wall is located in a recess of the support object and is held by a holding section of the support object that protrudes into the recess. The area of the separating wall that is in contact with the damping fluid can be increased, because the holding sections protrude only in certain areas into the recess.
According to an advantageous embodiment, it is provided that the channel stretches essentially in a radial direction concentric to the housing section.
Furthermore, it can be provided that the compensation chamber is defined by a formable element, especially one designed in the fashion of a rolling bellows that is braced between the seating and the support object. Manufacturing is simplified by the bracing being carried out in a fashion where the support object contacts the seating directly, because the thickness of the formable element of one bracing location has no influence on holding together the individual elements of the second anchoring member.
A particularly space-saving design is achieved in that the radial outer section of the channel wall, an outer section of the separating object and an outer section of the rolling bellows are arranged in an axial direction next to one another.
For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawing.